There’s one picture Emily posted that I want to mention. It shows sand grains taken by the Mars Hand Lens Imager (MAHLI), a camera on the rover that is capable of close-up images of the surface (the same one used to take the self-portrait). It’s a portion of this, a bigger image:

Look at that! Those are sand grains on Mars! This is the highest-resolution image ever taken on Mars by MAHLI, done by jockeying the camera closer to the surface than had ever been attempted before; again, see Emily’s post for the whole story, which is well worth your time.

I was curious (so to speak) about those pits in the sand, so I asked Emily, and she told me those are zap pits, blasted into the surface by Curiosity’s powerful laser! It vaporizes the material, which then glows from the heat. As it glows, a detector on the rover (called ChemCam) takes a spectrum of it, which reveals the chemical composition of the material.

By eye, I wouldn’t think twice if I scooped up sand like that here on Earth. Some of the grains are dark, some more glassy-looking. It could be the stuff I washed off my feet when I went to the beach not too far from where I grew up in Virginia.

Except it’s not. It’s on another world.

When that fact sinks in, really sinks in, it gives me chills. This is what we do, we humans. We send our proxies to other planets so that we may study them up close, and find out how they work. It’s simply and truthfully one of the noblest and best things we do.